This invention relates generally to timepieces having a date display, and more particularly, to an improved assembly that is able to facilitate viewing of the date because the date display can be made larger than in conventional timepieces with date displays.
Providing a date window in a timepiece, such as in an analog or chronograph watch has been known for many years, and accordingly, the basic mechanism, gear and dial movements used in connection therewith are quite old in the art.
However, certain styles of watches are designed to be small, such as those designed for a small wrist, such as in certain ladies style watches. For example, certain watch styles are designed both in a large version for a man, and a somewhat smaller although identical version for a woman. Unfortunately, as the watch casing size decreases, the circumference of the date ring (and corresponding size of the numbers thereon) needs to decrease, thus resulting in a calendar date feature that may be considered harder to see.
Accordingly, it would be desirable to provide a way to increase the size of the date that is viewed through the display. One way, of course, would be to either increase the size of the numbers on the date ring or the space available to display the date. While these may be satisfactory in some instances, they are less satisfactory than desired.
A more promising way to achieve satisfactory date display sizing is to utilize two date rings, one of which having printed thereon numbers from 0–9, while the other having the digits 1–3 printed thereon. While one such example can be found in DE 41 27 825, a more relevant construction has been proposed and was incorporated in a watch hereinafter believed to be sold under the name RONDA. Three figures showing the RONDA construction are set forth in FIGS. 7 and 8. However, for various reasons, it has been determined that such a constructions is less than desirable. For example, while FIG. 7 simply illustrates the outer date ring 100 and the inner date ring 110. FIG. 8 more particularly illustrates the mechanical workings thereof.
Specifically, FIG. 8 illustrates how an outer ring driving wheel 120 can be positioned to drive inner date ring 110. In turn, outer date ring 100 can be seen to rotate an intermediate wheel 120, by the meshing of teeth 105 on outer date ring 100 and corresponding teeth 125 and formed valleys on the outer surface of intermediate wheel 120. Therefore, it can be readily seen that each daily rotation of outer date ring 100 causes a corresponding rotation of intermediate wheel 120.
Furthermore, on intermediate wheel 120 is a finger 130, which has been highlighted for the convenience of the reader. Also readily viewable is a center wheel 140 (with a 110. Accordingly, the rotation of centerwheel 140 correspondingly rotates inner date ring 110.
The rotation of centerwheel 140 is caused by the engagement of finger 130 with the plurality of teeth 145. This engagement can be seen to occur once every 10th day. This is, each day outer date ring 100 can be seen to rotate about 360/20 degrees (taking into account that the outer ring digits are repeated only once). Likewise, each day, intermediate wheel rotates about 360/10 degrees, with finger 130 only engaging centerwheel 140 only once every 10th day.
This construction gives rise to at least one significant perceived disadvantage.
Specifically, it can be seen that if intermediate wheel 120 is positioned with finger 130 in any of the 9 positions other than the only one which will cause the proper advancing of centerwheel 140 and thus inter date ring 110, it is likely that inner date ring 110 may be caused to advance when the “one” digit in the window (not show) is other than the numeral “9”. This result may be caused due to a misalignment of intermediate wheel 120 during manufacture/repair of the watch itself, or may occur for example, if there is a meshing misalignment between teeth 125, for example (i.e. one of the teeth 105 may be damaged). Other easily envisioned misalignments are possible.
However, what is readily apparent is that the precision orientation of finger 130 with respect to the positioning of outer ring and/or the inner ring will be destroyed, thereby resulting in a permanent error in date advancement. For example, in one misalignment, the date will permanently advance for “08” to “19,” “18” to “29” and “28” to “09). Such a result is not readily fixable by the user without taking the entire watch apart.
Therefore, further developments to improve the size of the data displayed in the date window by utilizing two date rings are desirous, and are achieved by the present invention.